Second-order Møller-Plesset perturbation theory for molecular Dirac-Hartree-Fock wavefunctions. Theory for up to two open-shell electrons

✍ Scribed by Kenneth G. Dyall

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 552 KB
• Volume: 224
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(94)00488-9

✦ Synopsis

Moller-Plesset perturbation theory is developed to second order for a selection of Kramers-restricted Dirac-Hartree-Fock closed-and open-shell reference wavefunctions. The open-shell wavefunctions considered are limited to those with no more than two electrons in open shells, but include the case of a two-configuration SCF reference. Denominator shifts are included in the style of the OPT2 method of Murray and Davidson, but with a modification which avoids the orbital dependence of the original formulation. An implementation which uses unordered integrals with labels is described, and application to the ground state of the 02 molecule is presented.